Pressure sensing or monitoring devices are frequently employed in a wide variety of systems and equipment. In particular, vehicles and equipment employed in aerospace equipment and in ground and sea transportation or control applications require constant monitoring of specific pressure levels to assure continuous trouble-free operation of various components and systems.
Due to the variety of components typically being monitored, and the wide variety of applications and uses to which such equipment is subjected, the monitoring equipment is repeatedly exposed to substantial temperature changes. As a result, any pressure sensor or monitor must be constructed in a manner which will assure continuous, trouble-free operation regardless of the temperature changes to which the monitoring equipment is exposed. However, in spite of the requirement that pressure sensors or monitors should be capable of withstanding severe temperature changes, many prior art systems are incapable of providing the desired level of repeatable, reliable precision pressure monitoring under all such adverse conditions.
Typically, when exposed to broad changes in ambient temperatures, prior art pressure sensors or monitors are incapable of continuously functioning within a limited tolerance range. Although these prior art pressure sensors are completely capable of effectively operating and monitoring pressure levels or pressure changes at normal, standard ambient conditions, the exposure to substantial environmental changes causes the components of the pressure sensor to change, due to expansion or contraction. As a result of such and other physical changes within the pressure sensor itself, the pre-set thresholds originally incorporated into the sensor during its production are affected, causing actuation of the pressure sensor under conditions which substantially exceed the tolerances for proper operation of the pressure sensor.
Therefore, it is a principal object of the present invention to provide a pressure sensor or monitor which is capable of continuously monitoring pressure levels within limited tolerance ranges regardless of changes in the ambient temperature to which the sensor is exposed.
Another object of the present invention is to provide a pressure sensor or monitor having the characteristic features described above which is reliable and capable of repeatably functioning within the desired, pre-set, limited actuation standards or tolerances regardless of the temperature at which the sensor must perform.
Another object of the present invention is to provide a pressure sensor or monitor having the characteristic features described above which is constructed for rugged, long-term repeated use and for enduring substantially severe environmental conditions, without negatively affecting its operation or precision monitoring capabilities.
Another object of the present invention is to provide a pressure sensor or monitor having the characteristic features described above which is capable of being manufactured at a reasonable price.
Other and more specific objects will in part be obvious and will in part appear hereinafter.